Process for making ti-ni based functionally graded alloys and ti-ni based functionally graded alloys produced thereby

Abstract

The present invention relates to Ti—Ni based functionally graded alloys easy in proportional control, which are made by cold working and annealing Ti—Ni based alloys under a predetermined temperature gradient. The thus processed Ti—Ni based functionally graded alloys have a shape memory effect and an ultra elasticity and at the same time, have a consecutive variation of shape depending on a temperature variation.

1 . A process for making Ti—Ni based functionally graded alloys, wherein Ti—Ni based alloys are cold worked, annealed under a temperature gradient, and given functionally grading. 
   
   
       2 . The process of  claim 1 , wherein cold working is performed by 25% to 65% and annealing is performed under a temperature gradient of 823 K to 466 K. 
   
   
       3 . Ti—Ni based functionally graded alloys enabling a proportional control, made according to the process of  claim 1 . 
   
   
       4 . The alloys of  claim 3 , wherein a deformation-rate recovery speed of the alloys is reduced to 1/30 to 1/100. 
   
   
       5 . Ti—Ni based functionally graded alloys enabling a proportional control, made according to the process of  claim 2 .